Donetsk , Ukraine -LRB- CNN -RRB- -- Pro-Russia separatists in eastern Ukraine have decided to go ahead with a Sunday referendum on greater local powers , they said Thursday , defying a call by Russian President Vladimir Putin to postpone the vote .

Putin had urged the pro-Russia sympathizers to delay the referendum to give dialogue `` the conditions it needs to have a chance . ''

Representatives from the council of the self-declared Donetsk People 's Republic and separatists from Luhansk told reporters they have voted to press ahead to ask eastern Ukrainians there if they want sovereignty from Kiev .

`` After the vote that was held today , the unanimous decision was to go ahead with the referendum May 11 , '' Denis Pushilin , the self-declared chairman of the Donetsk People 's Republic said , according to Russian state news agency RIA Novosti .

Pushilin said Putin 's comments Wednesday were `` surprising '' but he respected him .

There was no immediate reaction from Moscow or Kiev .

Sunday 's referendum could echo events in March when voters in Crimea approved a controversial ballot to secede from Ukraine and join Russia , which subsequently annexed the Black Sea peninsula . The move escalated the turmoil rocking the country .

`` On the local ` referenda , ' we strongly emphasize that they should not take place -- neither on 11 May nor at any later date , '' said Maja Kocijancic , spokeswoman for the European Union 's top diplomat , Catherine Ashton . `` Such unauthorized local ` referenda ' have no democratic legitimacy and can only lead to further escalation . ''

Separatists have been defiant in the past . An international pact reached among Russia , Ukraine and its Western allies in Geneva , Switzerland , last month that called for the rebels to disarm and vacate buildings seized in the volatile region has not yet materialized .

In what seemed to signal a softening in Moscow 's attitude toward Kiev , Putin also said Wednesday that Ukrainian presidential elections scheduled for this month were `` a step in the right direction . ''

However , he also voiced caution .

`` But it will not solve anything unless all of Ukraine 's people first understand how their rights will be guaranteed once the election has taken place , '' Putin said , according to a Kremlin transcript following his meeting with the chairman of the Organization for Security and Cooperation in Europe .

Putin also said that direct talks between Kiev authorities and representatives of the pro-Russian sympathizers in southeast Ukraine were key to settling the crisis .

Ukrainian interim Prime Minister Arseniy Yatsenyuk dismissed Putin 's comments on the referendum as `` hot air . ''

Amid the diplomatic tit-for-tat , Russia 's Foreign Ministry said Thursday it had added names to its list of U.S. and Canadian officials barred from entering Russia , in response to sanctions impose by the United States and Canada on Russian officials .

NATO : No sign of Russian troop withdrawal

In a statement on his official website on Thursday , interim President Oleksandr Turchynov said his government was ready for dialogue with those who want to talk -- but not with `` armed criminals with blood on their hands . ''

`` Ukrainian authorities have never conducted punitive operations in the east , '' he said , responding to Russian accusations over Kiev 's military campaign to defeat the rebels who have overrun the east .

`` The law enforcement agencies protect the lives and health of the citizens in the framework of the anti-terrorist operation performed against terrorists , saboteurs , and other criminals who murder , torture , and kidnap our citizens . ''

Police in Luhansk confirmed Thursday that Valeriy Salo , a man named by the Kyiv Post as the kidnapped head of a pro-Ukrainian group in the Donetsk region , was found dead in a burned-out car near the Luhansk village of Petrovskiy .

Salo 's family told police that on Wednesday evening an unknown armed group arrived at their home and took Salo away . The Kyiv Post said he was captured by representatives of the Donetsk People 's Republic .

Rights group Amnesty International last month raised concern over the reported abduction of journalists and local officials by the Donetsk People 's Republic and other groups , and urged their immediate release .

Poll : Lack of confidence

A majority of Ukrainians agree their country should remain a unified state , according to a poll released Thursday .

The Pew Research Center poll , conducted in the first half of April , found that 77 % of Ukrainians want the country to remain united ; 70 % in the east feel the same . Things differ in Crimea , where 54 % of those surveyed voice support for the right to secede .

The survey also highlighted a lack of confidence in the new government that came to power after pro-Moscow President Viktor Yanukovych was ousted following months of protests . Just 41 % say the interim authorities are having a good influence on the way things are going .

`` Russia is viewed with the greatest suspicion . Three times as many Ukrainians say Russia is having a bad influence on their country as say it is having a good impact -LRB- 67 % vs. 22 % -RRB- , '' it said .

Meanwhile , NATO has n't seen `` any signs '' that Russia is withdrawing troops from Ukraine 's border , said Anders Fogh Rasmussen , the military alliance 's secretary-general .

`` So far we have n't seen any indications that they are pulling back their troops . Let me assure you that if we get visible evidence that they are actually pulling back their troops , I would be the very first to welcome it , '' Rasmussen told a news conference in the Polish capital .

White House deputy press secretary Josh Earnest also told reporters Wednesday that `` there is not evidence to date that there has been a meaningful and transparent withdrawal of Russian forces from the Ukrainian border . ''

The comments came after Putin announced a troop pullback Wednesday , saying Russian forces are `` now not on the Ukrainian border but are carrying out their regular exercises at the test grounds . ''

Kiev , its neighbors and Western governments have voiced alarm over what NATO estimates are around 40,000 Russian troops massed along the Ukrainian border . Moscow has repeatedly said they are only carrying out exercises .

The state-run ITAR-Tass news agency cited Russian Deputy Defense Minister Anatoly Antonov as saying Thursday that Ukraine has deployed a 15,000-strong military force near Russia 's borders . He reiterated Putin 's comments that Russia had pulled back from the border and said Moscow 's defense minister had informed U.S. Defense Secretary Chuck Hagel about this in a phone conversation .

Military offensive

Violence has escalated on the ground as tensions rise .

The State Department is now warning U.S. citizens to defer all non-essential travel to Ukraine . It also said Thursday that U.S. citizens should defer all travel to Crimea and eastern regions

Kiev last week launched its biggest military campaign yet to drive out pro-Russian militants who have reportedly taken over some public buildings in towns across southeast Ukraine .

Five pro-Russian activists were killed overnight Wednesday when Ukrainian forces attacked barricades on the outskirts of Mariupol , a spokeswoman for the pro-Russian camp said .

Elsewhere in the volatile Donetsk region , an uneasy standoff continued between the Ukrainian military and separatists .

Both sides clashed Monday at the rebel stronghold of Slovyansk . Ukraine 's security services said 30 `` heavily armed '' militants had been killed in recent days as part of the `` anti-terrorist '' operation in the area .

Kiev and many experts in the West believe the separatists are backed by Moscow and fear that Putin is fomenting trouble to increase his influence in the region . The Ukrainian authorities have accused Russian special forces of leading the rebellion in the field -- a claim Moscow denies .

In an interview with Al Jazeera , Ukrainian Foreign Minister Andrii Deshchytsia accused Russian troops -- which he says comprise special forces and intelligence -- of infiltrating and destabilizing the east of the country .

`` These well-equipped groups resort to guns , oppression and blackmail to intimidate people ... in an effort to channel them to their own purposes , and thus create the false impression that their demands are backed by broad public support , '' he said .

`` Russia 's major goal is to destabilize and control the country . We will not let this happen . ''

Moscow says right-wing , ultranationalist groups are behind the violence in Ukraine and that it has no direct influence over the pro-Russian groups .

The violence in Ukraine has created the worst East-West diplomatic crisis since the end of the Cold War .

However , French President Francois Hollande said Thursday that Putin would be welcome to attend next month 's ceremonies marking the 70th anniversary of D-Day in Normandy , northern France .

`` We may have differences with Vladimir Putin at the moment namely over the crisis in Ukraine but I have not forgotten and never will forget that the Russian people gave millions of lives -LRB- during World War II -RRB- , '' Hollande told local television in a clip posted on the presidential palace website .

`` That is why I told Vladimir Putin that as the representative of the Russian people , he is welcome to these ceremonies . ''

The government in Kiev is bracing for further unrest in the run-up to Friday 's national holiday to commemorate the end of World War II .

In a television address , Yatsenyuk urged Ukrainians not to take part in `` mass actions '' and not to respond to provocations . Kiev has said it is stepping up security measures ahead of the holiday .

A week in eastern Ukraine

Ukraine crisis : Small numbers , global impact

West threatens Russia with more sanctions

Opinion : Putin 's empire building is not a new Cold War

Journalist Lena Kashkarova reported from Donetsk and CNN 's Marie-Louise Gumuchian wrote and reported from London . CNN 's Nick Paton Walsh , Matthew Chance , Elaine Ly and Laura Smith-Spark contributed to this report , as did journalist Azad Safarov .

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NEW : Russia says more U.S. and Canadian officials have been added to those barred entry

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Donetsk and Luhansk separatists say they 're going ahead with Sunday referendum

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Body reportedly of pro-Ukrainian Donetsk resident is found in burned-out car

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Russia says it 's withdrawing troops from border , but NATO and U.S. see no signs of it